Thrust direction modification means



March 5, 1968 cs. R. PINTER THRUST DIRECTION MODIFICATION MEANS Filed March 9, 1966 INVENTOR. GEORGE R 'PINTER an 7mm ATTORNEYS United States Patent ()fiice 3,371,491 THRUST DIRECTION MODIFIQATION MEANS George R. Pinter, Hicitsviile, N.Y., assignor to Aerojet-General Corporation, Azusa, Calif., a corporation of (lino Filed Mar. 9, 1966, Ser. No. 532,981 8 Claims. (Cl. 60-230) The present invention relates generally to the thrust vector control of reaction propulsion motors and particularly to a means of producing thrust vector control by selectively setting up a condition of imbalance in the gas flow through the exhaust nozzle of reaction propulsion motors.

In reaction propulsion motors the products of combustion exhaust from the motor through an exhaust nozzle in which they flow at supersonic speed, low pressure and high temperature. Various methods of producing an alteration of the interior pressure distribution along the nozzle as a means of producing guidance forces have been suggested. Such methods however have required the addition of parts to the nozzle such as deflection devices or utilized sprays of fluid injected into the nozzle through openings in the wall thereof and in general have added considerable weight and complication to the structure of the motor or other reaction engine.

It is an object of the present invention to provide an improved method of and means for the thrust vector control of reaction propulsion motors by selectively varying the pressure acting along the interior of the nozzle.

Another object of the invention is to provide improved means for the thrust vector control of reaction propulsion motors without the addition of moving parts to the nozzle.

Yet another object of the invention is to provide improved means for the thrust vector control of reaction propulsion motors wherein shock waves are selectively produced adjacent to the inner surface of the exhaust nozzle by means of an electrical heating element.

Still further objects and features of the invention will hereinafter appear from the following description read together with the accompanying illustrative drawings wherein:

FIG. 1 is a fragmentary longitudinal section through the exhaust nozzle end of a reaction propulsion motor with electrical discharge points projecting into the exhaust nozzle near the throat thereof.

16. 2 is a fragmentary longitudinal section through a reaction propulsion motor exhaust nozzle having electrically heated resistance elements.

FIG. 3 is a fragmentary longitudinal section through an exhaust nozzle similar to FIG. 2 but having inductively heated elements.

Referring now to FIG. 1, the numeral indicates the after end of a reaction propulsion engine from which the burning gases exhaust through a nozzle 11. The exhaust nozzle 11 is designed to offer minimum resistance to the flow of the exhaust gases which leave the throat 12 of the nozzle 11 at supersonic speed and high temperature. Flow through the nozzle 11 is however at low pressure and may be easily deflected from the inner surface of the nozzle 11. The inner surface should therefore be free from irregularities since any disturbance of the flow of exhaust gas through the nozzle 11 will cause an imbalance of pressure acting on the motor or other vehicle and cause deviation of the vehicle from a straight line flight.

Two sets of spark or discharge points 13 and 14 respectively are shown mounted in opposite sides of the nozzle 1, the set 14 being shown in operation. The individual points can be molded in place as inserts in the nozzle 11. Conductors 15 and 16 for spark points 13 and conductors 17 and 18 for spark points 14 are connected to a suit- 3371,4 91 Patented Mar. 5, 1968 able source of electrical energy indicated as 19 and positioned within a housing 20 near the rear end of the motor.

Activation of the electrical energy source 19 will establish an electrical spark or are between individual spark points of the set 14. This arc or spark will cause localized heating near the inner surface of the nozzle 11 which will introduce a disturbance into the gas flow region within the exit cone. The disturbance will in turn produce an oblique-like shock wave 21 originating somewhat upstream from the point of disturbance. Since the pressure behind the shock Wave 21 will be higher than the pressure in the undisturbed areas at the same expansion ratio as other points of the nozzle, the forces in planes perpendicular to the axis of the nozzle 11 will not be balanced and will result in a turning moment or net force pointing towards the area of disturbance.

By positioning sets of spark points at various locations around the inner surface of the nozzle 11, net guidance forces can be produced to alter the thrust line of the rocket. The variable intensity frequency of AC sparks would provide even greater control than the simple establishment and extinguishment of a direct current arc.

The existence of low pressure in the nozzle is an aid to formation of the are or stream of sparks between discharge points in a set. While the spark points present obstruction to the flow of the exhaust gases so as not to cause unwanted turbulence, the heat of the electrical discharge is effective to set up a shock wave resulting in a controllable deviation of the thrust from an axis passing through the center of gravity of the vehicle.

In FIG. 2, electrical heating elements are shown as resistances 22 and 23 fitted into grooves in insulating plates 24 and 25 respectively set into recesses in the inner surface of the nozzle 11 and connected by conductors 26 and 27 to a suitable source of electrical energy.

In FIG. 3 electrical heating elements are shown as metal plates 28 and 29 set in insulation plates 30 and 31 fitted into recesses in the inner surface of the nozzle 11 Induction coils 32 and 33, arranged to interact with the heating plates 28 and 29 respectively are connected by conductors 34 and 35 to a suitable source of alternating current (not shown).

In both the embodiments shown in FIGS. 2 and 3 it is to be understood that a shock wave will be formed in the nozzle due to the heating element. As explained with respect to the device illustrated in FIG. 1, the localized heating will produce the desired shock wave. In each case there is practically no interference with the smooth flow of exhaust over the inner surface of the nozzle. The actual number and arrangement of the shock wave generating heat units will depend on the control of the thrust vector required.

Electrical power to operate the heat generting means of the invention may be of any suitable type, emphasis being placed on light weight and fast discharge. The showing of storage batteries in FIG. 1 is therefore to be understood as given by way of example only.

Preferred embodiments of the invention have been described and shown by way of illustration but not as limitations of the scope of the invention since various modifications of the described embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. A reaction propulsion motor comprising: (a) a combustion chamber for burning fuel and producing combustion gases, (b) a convergent-divergent exhaust nozzle operably associated with said combustion chamber for receiving said combustion gases and to accelerate said 3 combustion gases to supersonic velocities, and (c) means for electrically heating a portion of the inner surface of said exhaust nozzle so as to create a disturbance in the region adjacent to the area heated resulting in a shock wave which produces a controllable deviation from straight line flight.

2. The reaction propulsion motor of claim 1 wherein the means for electrically heating a portion of the inner surface of said exhaust nozzle comprises: (a) a set of spark points mounted in the inner surface of said exhaust nozzle, and (b) a source of electrical energy operably associated with said spark points so as to produce an electrical spark between said points when said source is actuated.

3. The reaction propulsion motor of claim 1 wherein the means for electrically heating a portion of the inner surface of said exhaust nozzle comprises: (a) a resistance heating element mounted in the inner surface of said exhaust nozzle and (b) a source of electrical energy operably associated with said resistance heating element so as to heat said element when said source is actuated.

4. The reaction propulsion motor of claim 1 wherein the means for electrically heating a portion of the inner surface of said exhaust nozzle comprises: (a) an inductively heated element mounted in the inner surface of said exhaust nozzle, (b) an induction coil mounted on the outer surface of said nozzle and operably associated with said inductively heated unit, and (c) a source of electrical energy operably associated with said induction coil so as to activate said coil and heat said unit when said source is actuated.

5. A thrust vector control system for reaction propulsion motors and the like comprising: (a) an exhaust nozzle having a convergent-divergent inner surface to accelerate gases received by said nozzle, (b) an electrical heating element mounted in the inner surface of said exhaust nozzle, and (c) a source of electrical energy operably associated with said electrical heating element so as to produce localized heat when said source is actuated thereby creating a disturbance in the gas flow resulting in a shock wave which produces a turning moment upon said nozzle.

6. The thrust vector control system of claim 5 wherein said electrical heating element comprises a set of spark points.

'7. The thrust vector control system of claim 5 wherein said electrical heating element comprises a resistance heating element.

8. The thrust vector control system of claim 5 wherein said electrical heating element comprises an inductively heated element operably associated with an induction coil.

References Cited UNITED STATES PATENTS CARLTON R. CROYLE, Primary Examiner. 

1. A REACTION PROPULSION MOTOR COMPRISING: (A) A COMBUSTION CHAMBER FOR BURNING FUEL AND PRODUCING COMBUSTION GASES, (B) A CONVERGENT-DIVERGENT EXHAUST NOZZLE OPERABLY ASSOCIATED WITH SAID COMBUSTION CHAMBER FOR RECEIVING SAID COMBUSTION GASES AND TO ACCELERATE SAID COMBUSTION GASES TO SUPERSONIC VELOCITIES, AND (C) MEANS FOR ELECTRICALLY HEATING A PORTION OF THE INNER SURFACE OF SAID EXHAUST NOZZLE SO AS TO CREATE A DISTURBANCE IN THE REGION ADJACENT TO THE AREA HEATED RESULTING IN A SHOCK WAVE WHICH PRODUCES A CONTROLLABLE DEVIATION FROM STRAIGHT LINE FLIGHT. 